What physiological changes occur in the body due to decompression sickness?

Decompression sickness, commonly known as "the bends," occurs when a diver ascends too quickly after a deep dive, causing nitrogen bubbles to form in the bloodstream and tissues. During a dive, the body absorbs nitrogen from the breathing gas under high pressure. If a diver surfaces too rapidly, the pressure decreases too quickly, and the nitrogen, which was dissolved under high pressure, forms bubbles.

These bubbles can cause a variety of symptoms, as they can block blood vessels and disrupt normal physiological functions. The formation of these bubbles is the primary cause of the symptoms associated with decompression sickness, such as joint pain, dizziness, and even serious neurological problems.

In contrast, increased blood pressure, excessive heat generation, and heightened alertness are not physiological changes typically associated with decompression sickness and do not occur as a direct result of the diver's ascent. Instead, the main physiological change is the formation of bubbles, making this the correct choice for the question.